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US 4,076,287 AGranted
Prepared joint for a tube fitting
AssigneeCaterpillar Tractor Co.
InventorsRoland F. Bill, Edward G. Prohaska, Bernard A. Wabel
Life of this patent
Estimating the term…
Abstract
An improved prepared joint is provided on a fitting for mechanically joining it to the end of a metal tube. The fitting has a grooved bore and a bore extending end portion for projecting the bore a predetermined distance beyond its grooved portion so that during radial expansion of the tube into the grooved portion the entire expanded length of the tube is fully supported within the fitting. Such support is effective in extending the useful life of the tube assembly formed by the fitting and tube by alleviating metal fatigue failures due to vibrational bending stresses in the expanded portion of the tube.
Claims18
A tube assembly, comprising:
- a flange having an axis, first, second, third, fourth and fifth portions as consecutively measured along the axis from a first end of the flange, an annular opening extending therethrough and defining inner walls, a plurality of annular grooves, at least one annular land, and an annular rear land, said opening of said first portion being of a first preselected diameter, said opening of said second portion being of a second preselected diameter, said opening of said third portion being defined by annular grooves of a third preselected diameter spaced one from the other by said annular land which has a fourth preselected diameter, said annular rear land having a fifth preselected diameter, said opening of said fifth portion being of a sixth preselected diameter, said second, fourth and fifth preselected diameters being of a substantially uniform, common value, said sixth preselected diameter being of a substantially uniform value greater than said second, fourth, and fifth preselected diameters, and said third preselected diameters being of a substantially uniform, common value greater than said sixth preselected diameter;
- a metal tube having first, second, third, fourth, fifth and sixth portions as consecutively measured from the first portion of the flange along the axis, said first, second, third, fourth and fifth tube portions extending into the flange opening, said first portion of the tube having an edge portion adjacent the first portion of the flange, said second and fifth portions of the tube being in forcible contact with inner walls of the respective second and fifth portions of the flange, portions of said third portion of the tube adjacent the annular land being in forcible contact with said annular land, portions of said third portion of the tube adjacent the annular grooves extending into said annular grooves, said fourth portion of the tube being in forcible contact with the annular rear land, and said sixth portion of the tube extending outwardly from the flange.
A tube assembly, comprising:
- a flange having an axis, a central opening extending along said axis, inner walls, a plurality of annular grooves extending about the inner walls, at least one annular land extending about the inner walls and separating the annular grooves one from the other, an annular rear land extending about the inner walls, an annular exit groove extending about the inner walls and having a predetermined length as measured along the axis and a uniform diametral dimension greater than the diametral dimension of said annular rear land;
- and
- a metal tube positioned within the flange opening and being deformed outwardly into forcible contact with the annular lands and the annular exit groove along the entire lengths thereof and deformed into the annular grooves, said annular grooves, metal tube and annular exit groove being of relative sizes sufficient for maintaining the internal diameter of the portion of the tube within the flange at a substantially uniform value and maintaining the external diameter of the portions of the tube immediately adjacent the flange at a value less than the external diameter of the portion of tube within the flange.
In a tube assembly including a substantially uniform deformable metal tube and a metal fitting having a prepared joint for mechanically joining the fitting onto one end of the tube, said prepared joint comprising:
- annular wall means defining an annular bore therethrough, said bore having an intermediate grooved portion therealong adapted for receiving the end of the tube and defining a plurality of longitudinally disposed alternating, annularly extending lands and locking grooves, said lands being of a substantially uniform diameter for initially axially slidably receiving said one end of the tube into the bore and said locking grooves having a predetermined substantially uniform depth sufficient to accommodate the amount of expanded metal of the tube necessary to form a secure mechanical joint therebetween after said mechanical joining wherein a predetermined length of the tube from its one end is radially expanded into tight sealing engagement against the grooved portion of the bore, said expanded length being sufficient so that a portion thereof extends a predetermined distance past the grooved portion of the bore for ensuring the substantial uniform extrusion of tube material into the locking grooves;
- and
- said annular wall means having a predetermined thickness for providing an extended end portion on the bore defining an elongated exit groove extending from an outermost land at one end of the grooved portion a distance greater than the distance that said portion of the expanded length of the tube extends for assuring that said portion of the expanded length of the tube is completely accommodated within the exit groove and is sufficiently radially expanded outwardly thereagainst so as to be supported entirely within the annular wall means and assuring a minimal amount of tube wall thinning occurring therein, said extended exit groove end portion having a substantially uniform diametral size greater than the diametral size of the unexpanded tube.
Dependencies are inferred from the claim text.